Dirt and surface contamination can affect the finish. Agree suitable ordinary cleaning as part of the preparation rather than assuming oil covers it. Structural deterioration, hazardous materials and repairs to unsound boards remain separate from a maintenance oiling task.
Provide the old product label if available. A penetrating oil maintenance treatment is different from applying a film-forming deck paint. An existing incompatible coating may need separate preparation, so a new oil should not be selected from colour preference alone.
The timber needs to accept the proposed product in the way its instructions require. Glossy residue, uneven wear or previous treatment can change absorption. Photos support planning, but an on-site suitability check may still be needed before the application method is confirmed.
Apply the compatible oil according to its coverage and application instructions to the agreed prepared accessible deck surface. Scope limits: Compatible penetrating-finish maintenance on sound timber only. No structural repairs, hazardous stripping, waterproofing systems or guaranteed restoration of damaged boards.